The noun squirrel, which appeared in Middle English in forms such as squyrel and squerell, is from Anglo-Norman and Old-French forms such as escuirel and escureul (Modern French écureuil), from the unattested Late-Latin form scuriolus, diminutive of an unattested altered form of the Latin word sciurus (biologists have retained the name Sciurus for the genus that includes the squirrels).

FOLK-ETYMOLOGICAL INTERPRETATION OF THE GREEK NAME

The noun sciurus in turn is a Latinisation of Greek σκίουρος (= skíouros), which has been interpreted – by folk etymology for some foreign name – as being a compound of σκιά (= skiá), shade, and οὐρά (= ourá), tail, meaning shadow-tailed.

It is true however that when the animal sits erect, it often raises its bushy tail up against its back and over its head as if to shade itself—cf. also bright-eyed and bushy-tailed.

DIALECTAL ENGLISH NAME

Similarly, skug, also spelt scug, a dialectal English name for squirrel, also meant shade (but this might be a case of homonymy, and the two words might be unrelated). In a letter written from London on 14th February 1773, the American statesman, inventor, and scientist Benjamin Franklin (1706-90) explained to his wife, Deborah:

Skugg, you must know is a common Name by which all Squirrels are called here, as all Cats are called Puss.

SQUIRREL AS A DEROGATORY NAME

The word squirrel was sometimes contemptuously applied to persons. For example, in Merie tales newly imprinted [and] made by Master Skelton Poet Laureat (London, 1567), the English poet John Skelton (circa 1460-1529) wrote, in the tale titled Howe the Cobler tolde maister Skelton, it is good sleeping in a whole skinne:

In the Parysshe of Dys where as skelton was Person, there dwelled a cobler, beyng halfe a souter, which was a tall man and a greate slouen, otherwyse named a slouche, The Kynges Maiestye hauynge Warres byyonde the sea. Skelton sayd to thys a forsayd doughtie man. Neybour, you be a tall man, and in the Kynges warres you must bere a standard. […] Thou shalte bee harnessed to keepe away the strokes frō thy skynne. […] Skelton dyd harnesse the doughtye Squirell, and dyd put an helmet on his head.

FRENCH ALTERNATIVE NAME – FRENCH PHRASES

In French, écureuil, squirrel, used to be also called jacquet, diminutive of the proper name Jacques, corresponding to English James. The obsolete French expression dès potron-jacquet means at the crack of dawn. Just like the interpretation of the Greek word skíouros, it originates in the fact that the squirrel often raises its tail: the word potron is related to postérieur (English posterior) and the expression literally means as soon as the squirrel’s posterior (can be seen). It has now been replaced by dès potron-minet, the latter word meaning pussycat.

GERMANIC NAMES

The native Old-English name of the squirrel was ácweorna, later ácwern (of which the first element is apparently oak). This name is cognate with the following Germanic words meaning squirrel: – German Eichhörnchen – Dutch eekhoorn – Swedish ekorre – Danish egern.

ROMANIC NAMES

In the Romance languages, the names are (the first three are based on Latin sciurus): – esquilo in Portuguese – esquirol in Catalan – scoiattolo in Italian – ardilla in Spanish (of uncertain origin) – veveriţă (from a Slavic word related to Latin viverra, ferret) in Romanian.

The Catalan word esquirol also denotes a strike-breaker, a blackleg (it has been adopted by Spanish in this sense), because it is said that, in the 19th century, striking workers in the Catalan town of Manlleu were replaced by workers from the town of L’Esquirol, also named Santa Maria de Corcó.